Step 1: Building the Car

I decided to build a 3 wheel car but it would be easy to build a 4 wheel car.

I found that bike inner tubes from thin tires can be cut in strips and fit perfectly over plastic bottle caps.

First glue the pulley wheel and bottle cap to the middle of a short skewer. Cut out a piece of cardboard for the car body. Cut out a slot for the back tire. Cut straw pieces and put them on the ends of the skewer. Glue the straws to the body with the pulley belt on the wheel. Glue skewers onto the cardboard to strengthen it. Glue the motor to the cardboard and make sure the pulley belt is straight and has the right tension. Glue one bottle cap to a skewer. Slide a straw over the skewer then glue the other cap to the other end. Wire the battery and motor with a switch. Glue the straw at an angle on the cardboard if you want the car to drive in circles. Glue the battery to the cardboard.